Class: Rack::Async

Inherits:
Object
  • Object
show all
Defined in:
lib/rack/async.rb

Defined Under Namespace

Classes: BlockingBody, BlockingCallback, CallbackBody

Constant Summary collapse

RESPONSE = 
[-1, {}, []].freeze
CALLBACK = 
"async.callback".freeze
BODY = 
"async.body".freeze

Instance Method Summary collapse

Constructor Details

#initialize(app) ⇒ Async

Returns a new instance of Async.



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# File 'lib/rack/async.rb', line 9

def initialize(app)
  @app = app
end

Instance Method Details

#call(env) ⇒ Object 



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# File 'lib/rack/async.rb', line 13

def call(env)
  original_callback = env[Async::CALLBACK]
  if original_callback.respond_to?(:arity)
    original_callback_arity = original_callback.arity
  elsif original_callback
    original_callback_arity = original_callback.method(:call).arity
  end
  
  if original_callback # we've got a thin-like async api!
    if original_callback_arity > 1 # wrap ebb's callback to expand the args
      env[Async::CALLBACK] = Proc.new do |response|
        original_callback.call(*response)
      end
    end
    env[Async::BODY] = Async::CallbackBody.new
  else # no async api, but blocking in the right places we can fake it
    blocking_callback = Async::BlockingCallback.new
    env[Async::CALLBACK] = blocking_callback
    env[Async::BODY] = Async::BlockingBody.new
  end
  
  response = @app.call(env)
  
  if response.first != Async::RESPONSE.first # non-async response
    response
  elsif original_callback && original_callback_arity > 1 # ebb-like
    [0, {}, []]
  elsif original_callback # thin-like
    Async::RESPONSE
  else # mongrel, etc
    blocking_callback.wait
  end
end